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jaysnote:v4l2_driver_framework_code_review [2018/11/12 15:33] jaylee |
jaysnote:v4l2_driver_framework_code_review [2021/06/22 23:14] |
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- | < | ||
- | # v4l2 drier framework code review | ||
- | |||
- | ## 术语解释 | ||
- | |||
- | | 术语 | 解释 | ||
- | | ---- | ------------------------ | | ||
- | | vfe | video front end driver | ||
- | | cci | camera control interface | | ||
- | | csi | camera serial | ||
- | |||
- | ## 启动流程 | ||
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- | ```bash | ||
- | $dmesg -T |egrep -i ' | ||
- | ``` | ||
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- | ![v4l2 driver lod sequecnce](http:// | ||
- | |||
- | 如上启动顺序 | ||
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- | * csi、cci、mipi 等外设初始化; | ||
- | |||
- | * vfe控制 v4l2 启动; | ||
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- | vfe在初始化 v4l2-device启动的时候已经同sub-device ov5640 通信,但是此时ov5640 启动还没有加载,这部分需要详细走读下代码; | ||
- | |||
- | * sub-device camera sensor ov5640 加载; | ||
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- | ## 驱动框架 | ||
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- | ![v4l2 驱动框架](http:// | ||
- | |||
- | ### kernel space | ||
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- | 1. vfe模块加载,加载csi、mipi、isp、cci模块,同时从sys_config读出sensor的配置; | ||
- | 2. 创建v4l2-device; | ||
- | 3. ov5640 通过cci/ | ||
- | 4. 创建video 设备节点 ; | ||
- | |||
- | ### userspace | ||
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- | * libv4l2 源码可以通过`sudo apt-get source libv4l2rds0` 下载。 | ||
- | |||
- | ```bash | ||
- | $ cat / | ||
- | deb http:// | ||
- | deb-src http:// | ||
- | ``` | ||
- | |||
- | > **注意**:如上,确定已经添加source 源。 | ||
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- | </ |